1. Field of the Invention
The present invention relates to a transparent medium processing device which processes a transparent medium (e.g. glass, plastic) using pulse laser beams.
2. Related Background Art
Technologies to process inside glass using laser is receiving heated attention recently. For example, technologies to implement an optical wave guide, optical memory, and-diffraction grating by changing the refractive index inside glass or modifying material inside glass is known, and these are highly anticipated as candidates to be devices which can perform such processing as computation by optically. Also in the field of micro-chemistry, micro-puncturing inside glass is necessary, and performing this by laser is being attempted.
If optimum optical pulses can be provided for such laser processing, flexibility in processing shapes improves, and the energy required for processing can be decreased. Also to popularize a device which requires rework non-periodically, an inexpensive light source is desired, so in order to popularize a three-dimensional optical memory built in to a standard computer, for example, a semiconductor laser is preferable as the light source, however it is necessary to set conditions to optimize the processing efficiency so that sufficient processing can be performed with the light quantity of a semiconductor-laser.
In this way, in order to implement glass processing appropriately, it is necessary to provide optical pulses in an optimum status according-to the processing target and processing content. However even if optical pulses are set in an optimum status, the laser light entering the processing target is not always in an optimum status at the processing point. For example, the dispersion of light is high inside glass, and it cannot be ignored that the medium exhibits non-linearity with respect to strong pulses, so the laser beam deviates from the set optimum status at the processing point.
Therefore it is desirable to monitor the processing point while processing with irradiating laser beams on the processing target, and to feed back this information so that the optical pulse are adjusted to obtain the desired processing result. For feedback, however, what is monitored is critical, but only X-rays and fluorescent lights, which are emitted as an indirect result of laser processing, or the transmitted light of the laser beam used for processing, are monitored in the case of the examples recently attracting attention, where the optimum status is not setup.
With the foregoing in view, it is an object of the present invention to provide a transparent medium processing device which monitors the status of light at a location (processing point) where interaction between a laser beam for processing and a processing target occurs when the transparent medium is processed by a laser beam so that the transparent medium can be processed in an optimum status.
A transparent medium processing device according to the present invention comprises: a light source section for generating a laser beam with a wavelength which has transparency with respect to a processing target, a light control section for executing variable control for the status of a laser beam emitted from the light source section, an incident optical system section for entering the laser beam controlled by the light control section to the processing target, and a light status measurement section for measuring the status of the laser beam inside the processing target, wherein the light control section is adjusted based on the output of the light status measurement section so that the status of the laser beam inside the processing target becomes a desired status.
According to the present invention, the status of the laser beam inside the processing target which is made of such a transparent medium as glass is measured by the light status measurement section and is fed back to the light control section, where the status of the laser beam emitted from the light source section is variably-controlled, so the status of the laser beam inside the processing target is adjusted to be a desired status. Therefore laser processing can be executed while maintaining the optimum status at the processing point.
In the present invention, it is preferable that the light source section is a pulse laser light source for generating a femto-second pulse laser beam, and it may be characterized in that the light control section includes a time waveform shaping section for shaping a time waveform of the laser beam, or includes a spatial form shaping section for shaping a spatial form of the laser beam, or includes a wave front control section for controlling a wave front of the laser beam, or has a configuration which is combined thereof.
In the present invention, it may be characterized in that the light status measurement section further comprises a light track observation unit for detecting the track of the laser beam inside the processing target, or it may be characterized in that the light status is measured by observing the scattered light from inside the processing target, or the light status is measured by observing with a streak camera after dispersing the scattered light from the inside of the processing target by a spectroscope, or the light status is measured by observing the scattered light from the inside of the processing target with a pulse width monitor.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.